I'm having a problem displaying data from a function to text box within a tab. If you run the code and click "Select Tab 2 and Fill..." I get an error; "TypeError: Error #1009: Cannot access a property or method of a null object reference." I'm guessing this is because "Tab 2" is/was not rendered yet. Now if I run the code, select "Tab 2" then select "Tab 1" and click "Select Tab 2 and Fill..." it works the way I would like. Dose any one know a way around this problem.

----Full Flex 4/Flash Builder Code just copy paste----

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
                       xmlns:s="library://ns.adobe.com/flex/spark" 
                       xmlns:mx="library://ns.adobe.com/flex/halo"
                       creationComplete=" ">    
    <fx:Script>
        <![CDATA[           
            public function showtab2():void
            {
                mytextbox.text="I made it!";
                tn.selectedIndex=1;
            }
        ]]>
    </fx:Script>
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <mx:Panel title="TabNavigator Container Example" height="90%" width="90%" 
              paddingTop="10" paddingLeft="10" paddingRight="10" paddingBottom="10">

        <mx:Label width="100%" color="blue"
                  text="Select the tabs to change the panel."/>

        <mx:TabNavigator id="tn"  width="100%" height="100%">
            <!-- Define each panel using a VBox container. -->

            <mx:VBox label="Panel 1">
                <mx:Label text="TabNavigator container panel 1"/>
                <mx:Button label="Select Tab 2 and Fill with Text" click="showtab2()"/>
            </mx:VBox>

            <mx:VBox label="Panel 2">
                <mx:Label text="TabNavigator container panel 2"/>
                <s:TextInput id="mytextbox" />
            </mx:VBox>

        </mx:TabNavigator>

        <mx:HBox>
        </mx:HBox>

    </mx:Panel>

</s:WindowedApplication>